A tremolo is a device which, when fitted to a stringed instrument, allows the player of the instrument to lower or raise the pitch of a note or chord. The device is commonly used with an electric guitar, and is sometimes referred to as a whammy bar or vibrato. Use of the tremolo allows a guitarist to temporarily increase or decrease the tension on the strings thereby to raise or lower the pitch.
Electric guitars are made with a neck and a body and a bridge. The bridge is usually fixed or a floating tremolo bridge or some other style of tremolo bridge. On guitars fitted with floating tremolo bridges the strings are attached to the tremolo bridge and drawn across the body and neck over a nut and fixed to an individual machine head. The strings are tensioned and tuned to pitch by the machine heads before the guitar is played. The tremolo includes the floating tremolo bridge pivotally attached to the guitar body. The tremolo also includes a lever that can be moved upwards and downwards to pivot the tremolo bridge. The tremolo is maintained in balanced position by the tensioned strings and one or more opposing balancing springs.
However, continuous use of the tremolo may cause stretching of the guitar strings. If the strings are overstretched, they will become plastically deformed and may not return to the original tuned pitch. If overstretched the strings may even break. With guitars employing existing tremolo mechanisms, if one of the guitar strings breaks or is plastically deformed, the balancing spring in the tremolo will pull on and increase the tension on the remaining strings causing the remaining strings to play at a higher pitch than originally tuned. Furthermore, springs operating the tremolo may also become stretched overtime, and therefore have the effect of lowering the strings' pitch. The guitars fitted with tremolo devices therefore often require more frequent re-tuning.
Furthermore, some guitarists bend strings as part of their playing technique. This technique involves the guitarist using their fingers to push the strings significantly out of line to raise the tension and increase the pitch of the strings. If the guitar is fitted with a “floating bridge” tremolo, the “bending” of one or more of the guitar strings will cause pulling on the bridge causing the unbent strings to lose tension. This results in the non-bent strings playing at a lower pitch than the originally tuned pitch.
When guitar strings are plucked they will vibrate to produce sound. The amplitude of these sound vibrations reduces with time. The length of time that these vibrations continue after the strings are plucked is known as the sustain time. The sustain time is reduced when these vibrations are damped. In the situation where the strings have been stretched or have lost tension from continuous use of the tremolo or when the guitarist employs string bending techniques, the sustain time for the affected strings maybe shortened.
Strings change pitch when their length and their tension are altered. For the guitar strings to maintain their tuned pitch, it is important that the neck and body remain dimensionally stable and rigid under normal playing conditions. Because they are flexed and stretched when they are plucked, it is equally important that the strings are free to move unrestricted over the nut and saddles and that they negotiate as few hard bends as possible along their length. It is further important that the strings do not bind up at any point along their length.
It is also important that the tremolo bearings are as friction free as possible and do not bind up in any operating position.
Existing tremolos suffer a number of problems as described above, and do not exhibit ideal characteristics such as maintaining the pre-existing in tune string pitch after the use of the tremolo. If any one string loses pitch it will cause all others to change pitch in response. This requires guitarists to constantly retune their guitars to address these problems. Constant retuning is time consuming and lessens the enjoyment of playing the instrument, and is impractical as a long term solution.